Aorto-enteric Fistula After Endovascular Abdominal Aortic Aneurysm Repair: Case Report and Review

Secondary aortoenteric fistula: a narrative review of the view of the surgeon

Aortoenteric fistula (AEF) is defined as the abnormal communication between the aorta and the gastrointestinal tract. AEFs are divided into primary and secondary usually after abdominal aortic aneurysm (AAA) recovery and are a rare but quite dangerous cause of gastrointestinal bleeding that the general surgeon may face during his/her career. Secondary AEF was first described in 1953 to a 44-year-old woman 3 months after an AAA operation. This review presents the role of the surgeon in the management of secondary aortoenteric fistulas. AEFs are a rare but fatal gastrointestinal bleeding cause that the general surgeon may be asked to manage. Diagnosis requires the combination of strong clinical suspicion and the presence of a history of AAA surgery. Although a vascular surgery case, general surgeons play a role in choosing the technique of restoring the intestinal tract, which seems to be significantly related to subsequent morbidity and mortality.

A Modern Series of Secondary Aortoenteric Fistula - A 19-Year Experience

OBJECTIVES

Secondary aortoenteric fistula is a rare and life-threatening condition. Clear evidence on the ideal therapeutic approach is largely missing. This study aims to analyze symptoms, etiology, risk factors, and outcomes based on procedural details.

PATIENTS AND METHODS

All patients with secondary aortoenteric fistula admitted between 2003 and 2021 were included. Patient characteristics, surgical procedure details, and postoperative outcomes were analyzed. Outcomes were stratified and compared according to the urgency of operation and the procedure performed. Descriptive statistics were used. The primary endpoint was in-hospital mortality.

RESULTS

A total of twentytwo patients (68% male, median age 70 years) were identified. Main symptoms were gastrointestinal bleeding, pain, and fever. From the twentytwo patients ten patients required emergency surgery and ten urgent surgery. Emergency patients were older on average (74 vs 63 years, P = .015) and had a higher risk of postoperative respiratory complications (80% vs 10%, P = .005). Primary open surgery with direct replacement of the aorta or an extra-anatomic bypass with an additional direct suture or resection of the involved bowel was performed in sixteen patients. In four patients underwent endovascular bridging treatment with the definitive approach as a second step. Other two patients died without operation (1x refusal; 1x palliative cancer history). In-hospital mortality was 27%, respectively. Compared to patients undergoing urgent surgery, those treated emergently showed significantly higher in-hospital (50% vs 0%, P = .0033) mortalities.

CONCLUSION

Despite rapid diagnosis and treatment, secondary aortoenteric fistula remains a life-threatening condition with 27% in-hospital mortality, significantly increased upon emergency presentation.

Infection of Vascular Prostheses: A Comprehensive Review

Vascular graft or endograft infection (VGEI) is a complex disease that complicates vascular-surgery and endovascular-surgery procedures and determines high morbidity and mortality. This review article provides the most updated general evidence on the pathogenesis, prevention, diagnosis, and treatment of VGEI. Several microorganisms are involved in VGEI development, but the most frequent one, responsible for over 75% of infections, is Staphylococcus aureus. Specific clinical, surgical, radiologic, and laboratory criteria are pivotal for the diagnosis of VGEI. Surgery and antimicrobial therapy are cornerstones in treatment for most patients with VGEI. For patients unfit for surgery, alternative treatment is available to improve the clinical course of VGEI.

COVID-19 induced aorto duodenal fistula following evar in the so called "negative" patient

OBJECTIVES

Since October 2019, SARS-CoV-2 pandemic represents a challenge for the international healthcare system and for the treatment and survival of patients. We normally focus on symptomatic patients, and symptoms can range from the respiratory to the gastrointestinal system. In addition, we consider patients without fever and respiratory symptoms, with both a negative RT nasopharyngeal swab and lung CT, as a "Covid-19 negative patient." In this article, we present a so called Covid-19 "negative" patient, with an unsuspected vascular clinical onset of the viral infection.

METHODS

An 80 y.o. man, who previously underwent endovascular aortic repair for an infrarenal abdominal aortic aneurysm, presented to our department with an atypical presentation of an aorto-enteric fistula during the pandemic. While in hospital, weekly nasopharyngeal swab tests were always negative for SARS-CoV-2. However, the absence of aortic endograft complications, the gross anatomy of duodenal ischemic injury, and the recent history of the patient who lived the last months in Bergamo, the Italian city with the highest number of COVID-19 deaths, lead the senior Author to suspect an occult SARS-CoV-2 infection. The patient underwent to resection of the fourth portion of the duodenum and the first jejunal loop, with subsequent duodenum-jejunal latero-lateral anastomosis and the direct suture of the aortic wall. The intestinal specimen was investigated as suspected SARS-CoV-2 bowel infection by the means of immune-histochemistry (IHC). An ileum sample obtained in the pre-COVID-19 era was used as a control tissue.

RESULTS

The histological analysis of the bowel revealed sustained wall ischemia and liponecrosis of the duodenal wall, with intramural blood vessels thrombosis. Blood vessel endotheliitis and neo-angiogenesis were also observed. Finally, the IHC was strongly positive for SARS-CoV-2 RNA and for HLA-G presence, with a particular concentration both in blood vessels and in the intestinal villi. The control tissue sample was not positive for both SARS-CoV-2 and HLA-G.

CONCLUSIONS

Coronavirus pandemic continues to be an international challenge and more studies and trials must be done to learn its pathogenesis and its complications. As for thromboembolic events caused by SARS-COV-2, vascular surgeons are involved in treatment and prevention of the complications of this syndrome and must be ready with general surgeons to investigate atypical and particular cases such as the one discussed in this article.

Intermittent endoleak via an aneurysm–iliac venous fistula after endovascular aneurysm repair

We have reported the rare case of an intermittent endoleak via an aneurysm–venous fistula (AVF). An 89-year-old woman had experienced postoperative sac expansion 6 years after she had undergone endovascular aneurysm repair. During aneurysmorrhaphy, we detected a small AVF, which was the source of the endoleak responsible for the aneurysmal sac expansion. This AVF had a check valve-like mechanism that allowed the inflow of blood from the iliac vein to the sac when the venous pressure exceeded the endotension. Our case has demonstrated the occurrence of an AVF after endovascular aneurysm repair that had resulted in an endoleak that was invisible on imaging studies and the presence of endotension.

First case report of gastric outlet obstruction due to aortofemoral bypass Dacron graft erosion of the duodenum treated with neo aortoiliac system procedure

INTRODUCTION

Gastric outlet obstruction is an uncommon complication of surgical treatment of aortoiliac occlusive disease with aortofemoral bypass. The most frequent presenting feature of duodenal erosion due to aortic synthetic graft is upper gastrointestinal bleeding, which can range from a minor "herald" bleed to exsanguinating hemorrhage.

CASE PRESENTATION

A 64-year-old male patient with an aortofemoral Dacron bypass due to aortoiliac occlusive disease TASC II D with a chronic graft infection required emergency resection of the right limb of the Dacron graft two years ago. The patient developed abdominal pain, postprandial vomiting and progressive weight loss with an upper gastrointestinal endoscopy that showed Dacron graft material eroding into the fourth portion of the duodenum generating a gastric outlet obstruction without aortoenteric fistula and ulceration in the duodenal mucosa.

CLINICAL DISCUSSION

The treatment goals of aortoenteric fistula are to control hemorrhage, treat infection, maintain adequate distal perfusion, graft explantation and aortic reconstructions like in this case. Traditional treatment of aortoenteric fistula is graft excision and establishing an anatomic autologous or an extra-anatomic synthetic bypass. Neo aortoiliac system procedure has shown to be the most effective and safest emerging technique today.

CONCLUSION

Aortoenteric fistula is a life-threatening condition associated with high morbidity and mortality and it can also pose a diagnostic dilemma. There are many presentations of aortoenteric fistula including gastric outlet obstruction syndrome. The neo aortoiliac system procedure is the ideal curative surgical approach in stable patients.

Intraoperative endoprosthesis customization for repair of an aortoenteric fistula in an emergency context: a case report

Aortoenteric fistula is a severe clinical condition and its management remains a major technical challenge for surgeons. In these cases, the conventional surgical approach is associated with high rates of morbidity and mortality. Endovascular surgery is an excellent option in these cases, but considering that the aorta has been treated previously, anatomy may not be compatible with commercially available endovascular devices and so physician-modified endografts may be needed in urgent cases. The case reported involves a secondary aortoenteric fistula, treated on an emergency basis with endovascular techniques, using a physician-modified endograft.

Aortic Fistulas: Pathophysiologic Features, Imaging Findings, and Diagnostic Pitfalls

Fistulas between the aorta and surrounding organs are extremely rare but can be fatal if they are not identified and treated promptly. Most of these fistulas are associated with a history of trauma or vascular intervention. However, spontaneous aortic fistulas (AoFs) can develop in patients with weakened vasculature, which can be due to advanced atherosclerotic disease, collagen-vascular disease, vasculitides, and/or hematogenous infections. The clinical features of AoFs are often nonspecific, with patients presenting with bleeding manifestations, back or abdominal pain, fever, and shock. Confirmation with invasive endoscopy is often impractical in the acute setting. Imaging plays an important role in the management of AoFs, and multiphasic multidetector CT angiography is the initial imaging examination of choice. Obvious signs of AoF include intravenous contrast material extravasation into the fistulizing hollow organ, tract visualization, and aortic graft migration into the adjacent structure. However, nonspecific indirect signs such as loss of fat planes and ectopic foci of gas are seen more commonly. These indirect signs can be confused with other entities such as infection and postoperative changes. Management may involve complex and staged surgical procedures, depending on the patient's clinical status, site of the fistula, presence of infection, and anticipated tissue friability. As endovascular interventions become more common, radiologists will need to have a high index of suspicion for this entity in patients who have a history of aneurysms, vascular repair, or trauma and present with bleeding. Online supplemental material and the slide presentation from the RSNA Annual Meeting are available for this article. ^©RSNA, 2021.

A rare case of sudden death due to aortogastric fistula after endovascular aortic repair of the descending aorta

Aortogastric fistulas are a rare type of aortoenteric fistula (AEF). Aortoenteric fistulas have been reported as a complication of endovascular aortic repair (EVAR) after the placement of prosthetic materials. Considering the anatomic relationship of the descending thoracic aorta and the stomach, the formation of an aortic fistula involving the stomach is an extremely rare case. We report the case of a 77-year-old woman who was admitted to the hospital due to severe mid-thoracic chest pain and was diagnosed with upper gastrointestinal bleeding. Her medical history included an aneurysm of the descending thoracic aorta, which was treated using the Thoracic Endovascular Repair (TEVAR) method several months prior. The patient died a few hours later amid hemorrhagic shock. The autopsy confirmed the upper gastrointestinal bleeding and revealed a fistula between the descending thoracic aorta and stomach, which were in anatomic contact because of a sliding hiatus hernia.

Aortoenteric Fistula after Endovascular Aneurysm Repair

Aortoenteric fistula is a rare complication following endovascular abdominal aortic aneurysm repair. However, there is a significant morbidity and mortality associated with this complication. Patients can present with gastrointestinal hemorrhage, fever, or nonspecific features of chronic infection. Extra anatomic bypass with complete graft explanation is the standard management.

Recurrence of Aortoenteric Fistula after Endovascular Aortic Repair

Aortoenteric fistula (AEF) after endovascular aortic repair (EVAR) is a rare complication, with only 32 cases reported previously. A 71-year-old man who presented with severe duodenal bleeding due to primary AEF (PAEF) underwent successful EVAR. Four years later, the AEF recurred because of dilatation of the aneurysm sac. He underwent emergent surgery, removal of the stent graft, and replacement of an artificial bifurcated graft with placement of a greater omental flap. EVAR for PAEF was an effective option for acute treatment, but it caused refistulization in the long term. EVAR should be considered as a bridge therapy to definitive surgery.

Secondary Aorto-enteric Fistula and Type II Endoleak Five Years after Endovascular Abdominal Aortic Aneurysm Repair

Introduction

Secondary aorto-enteric fistula (AEF) after endovascular abdominal aortic aneurysm repair (EVAR) is a rare but potentially fatal disease. The aetiology and mechanisms are unclear. This study presents a patient who developed secondary AEF and type II endoleak five years after EVAR.

Case

A 73 year old man underwent successful EVAR with a bifurcated aortic stent graft for a 5.5 cm infrarenal abdominal aortic aneurysm. The aneurysm sac showed no change in size for three years, then shrank 20 mm to 3.5 cm by five years. After five years and eight months, the patient presented with fever and back pain. Enhanced CT demonstrated enlargement of the aneurysm sac, type II endoleak from the third and fourth right lumbar arteries, and air around the stent graft. An emergency operation was performed. The infected stent graft was removed by pushing up the stent graft to release the hooks from the wall of the aorta. A small fistula resembling a fish mouth measuring 1×1 cm was observed in the third part of the duodenum. The fistula was closed by direct suture, and in situ reconstruction was performed with an 18×9 mm standard polyethylene terephthalate graft. Culture of the explanted stent graft grew enterobacter. Intravenous antibiotic therapy was continued for six weeks and was stopped after confirming no recurrence of infection with computed tomography and laboratory testing. Two years later, there has been no recurrence of infection.

Conclusion

Long term surveillance is critical because AEF can occur even after initially successful EVAR.

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Secondary aorto-enteric fistula post endovascular abdominal aortic aneurysm repair can occur in the late phase of follow up.

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Staged omentopexy may be beneficial for prevention of recurrent infection.

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Type II endoleak can affect the development of secondary aorto-enteric fistula.

Secondary aortoenteric fistula possibly associated with continuous physical stimulation: a case report and review of the literature

BACKGROUND

Secondary aortoenteric fistula is a rare but fatal complication after reconstructive surgery for an aortic aneurysm characterized by abdominal pain, fever, hematochezia, and hematemesis, and the mortality rate is high. It has been suggested that it arises due to either continuous physical stimulation or prosthesis infection during primary surgery. We describe an aortoenteric fistula following reconstructive surgery for an abdominal aortic aneurysm together with postmortem pathological findings.

CASE PRESENTATION

A 59-year-old Japanese man who had undergone reconstructive surgery for an abdominal aortic aneurysm 20 months earlier presented with the chief complaint of hematochezia and malaise. Esophagogastroduodenoscopy and total colonoscopy revealed only colon diverticula with no bleeding. Contrast-enhanced computed tomography revealed gas within the aneurysm sac and adhesion between the replaced aortic graft and intestinal tract, suggesting a graft infection. After 18 days of antibiotic treatment, he suddenly went into a state of shock, with massive fresh bloody stool and hematemesis, followed by cardiac arrest. An autopsy revealed communication between the artery and the ileum through an ulcerative fistula at the suture line between the left aortic graft branch and the left common iliac artery. Pathological analysis revealed tight adherence between the arterial and intestinal walls, but no marked sign of infection around the fistula, suggesting that the fistula had arisen due to physical stimuli.

CONCLUSIONS

Pathological analysis suggested that the present secondary aortoenteric fistula arose due to physical stimuli. This reaffirms the importance of keeping reconstructed aortas isolated from the intestine after abdominal aortic aneurysm surgery.

Current status of endovascular treatment of aortoenteric fistula

Aortoenteric fistula (AEF) is one of the most challenging diagnostic and therapeutic entities in vascular surgery. AEF can occur either primarily involving the aorta and the gastrointestinal tract or, more commonly, secondary to previous aortic reconstructive surgery. Traditionally, the treatment of AEF includes graft excision and extra-anatomic bypass surgery or in situ graft replacement. However, recently endovascular repair has emerged as an alternative therapeutic option. In this article, we present published and current evidence for endovascular repair of primary and secondary AEF. When endovascular treatment is applied where appropriate, early outcomes seem to be superior compared to open surgery. This benefit may be lost during long-term follow-up, implying that a staged approach with early conversion to in situ grafting may realize the best patient survival and morbidity. Lifelong administration of antibiotics is associated with a reduction in re-infection. An endovascular approach used as a bridging procedure in unstable patients is recommended, followed by definitive open therapy, if feasible, in patients with good life expectancy.

Abdominal Aortic Emergencies

This article discusses abdominal aortic emergencies. There is a common thread of risk factors and causes of these diseases, including age, male gender, hypertension, dyslipidemia, and connective tissue disorders. The most common presenting symptom of these disorders is pain, usually in the chest, flank, abdomen, or back. Computed tomography scan is the gold standard for diagnosis of pathologic conditions of the aorta in the hemodynamically stable patient. Treatment consists of a combination of blood pressure and heart rate control and, in many cases, emergent surgical intervention.

A Rare Cause of Primary Aortoenteric Fistula: Streptococcus parasanguinis Aortitis

Primary aortoenteric fistula is a rare cause of upper gastrointestinal bleed but can lead to significant mortality if the diagnosis is delayed. Aortitis, characterized by inflammation of the aortic wall, is a rare cause of aortoenteric fistula. We present a case report of a 72-year-old male patient with infectious aortoenteric fistula secondary to Streptococcus parasanguinis, along with a review of the literature. This case demonstrates the importance of early diagnosis and aggressive surgical treatment of aortoenteric fistulae and recognizing infectious aortitis as a potential etiology.

Editor's Choice - Management of Secondary Aorto-enteric and Other Abdominal Arterio-enteric Fistulas: A Review and Pooled Data Analysis

OBJECTIVES

To compare management strategies for secondary abdominal arterio-enteric fistulas (AEFs).

METHODS

This study is a review and pooled data analysis. Medline and Scopus databases were searched for studies published between 1999 and 2015. Particular emphasis was given to short- and long-term outcomes in relation to AEF repair type.

RESULTS

Two hundred and sixteen publications were retrieved, reporting on 823 patients. In-hospital mortality was 30.7%. Open surgery had higher in-hospital mortality (246/725, 33.9%), than endovascular methods (7/98, 7.1%, p < .001, OR 6.7, 95% CI 3-14.7, including staged endovascular to open surgery, 0/13, 0%). In-hospital mortality after graft removal/extra-anatomical bypass grafting was 31.2% (66/226), graft removal/in situ repair 34% (137/403), primary closure of the arterial defect 62.5% (10/16), and for miscellaneous open procedures 41.3% (33/80), p = .019. Among the subgroups of in situ repair, homografts were associated with a higher mortality than impregnated prosthetic grafts (p = .047). There was no difference in recurrent AEF-free rates between open and endovascular procedures. Extra-anatomical bypass/graft removal and in situ repair had a lower AEF recurrence rate than primary closure and homografts. Late sepsis occurred more often after endovascular surgery (2-year rates 42% vs. 19% for open, p = .001). The early survival benefit of endovascular surgery was blunted during follow-up, although it remained significant (p < .001). Within the in situ repair group, impregnated prosthetic grafts were associated with the worst overall and AEF related mortality free rates and vein grafts with the best. No recurrence, sepsis, or mortality was reported following staged endograft placement to open repair after a mean follow-up of 16.8 months (p = .18, p = .22, and p = .006, respectively, compared with patients in other groups).

CONCLUSIONS

Endovascular surgery, where appropriate, is associated with better early survival than open surgery for secondary AEFs. Most of this benefit is lost during long-term follow-up, implying that a staged approach with early conversion to in situ vein grafting may achieve the best results in selected patients.

The emergency medicine approach to abdominal vascular graft complications

INTRODUCTION

Abdominal aortic aneurysm (AAA) is a deadly condition, particularly with rupture. Emergency physicians provide vital frontline care to the diagnosis and treatment of this disease. Endovascular aortic repair (EVAR) has become the gold standard for treatment of AAA, but the management of EVAR complications is not well discussed in the emergency medicine literature.

OBJECTIVE OF THIS REVIEW

The purpose of this article is to provide an emergency medicine-focused review of the complications of EVAR.

DISCUSSION

Although many complications may arise after AAA repair, the most common include aortoenteric fistula, endoleak, limb ischemia, and graft infection. All potential complications should receive vascular surgery consultation and hemodynamic resuscitation. Aortoenteric fistula often presents nonspecifically with gastrointestinal (GI) bleeding, abdominal pain, and vomiting. Computed tomography with intravenous contrast is required for diagnosis. An endoleak is defined by vascular flow outside of the graft. The optimal diagnostic modality includes triple phase computed tomographic scan (noncontrast, arterial, delayed phase). Limb ischemia may occur before 2 months, or in a later period, with symptoms ranging from claudication to complete neurovascular compromise. Graft infection is most commonly due to Staphylococcus aureus, and imaging can suggest the diagnosis. Definitive diagnosis requires tissue or fluid sampling. Through an understanding of these complications, emergency physicians may improve patient outcomes.

CONCLUSIONS

With the growing use of EVAR, emergency physician exposure to complications of this procedure is increasing. Knowledge of the complication presentations, diagnoses, and management can play an integral role patient care.

An Aortoenteric Fistula Arising after Endovascular Management of a Mycotic Abdominal Aortic Aneurysm Complicated with a Psoas Abscess

Mycotic aortic aneurysms account for 1-3% of all aortic aneurysms. The management of this disease is controversial. Since open surgical repair is associated with high morbidity and mortality rates, endovascular aneurysm repair is an alternative treatment method with promising early and midterm outcomes, although its long-term durability is unknown. Secondary aortoenteric fistulas may occur iatrogenically after either aortic reconstructive surgery or endovascular repair. As the number of aneurysms managed with endovascular aneurysm repair has substantially increased, cases of aortoenteric fistulas referred for endovascular repair are augmented. We report the case of an aortoduodenal fistula manifested with duodenal perforation after staged endovascular and surgical treatment of a mycotic aortic aneurysm.

Primary Aortoenteric Fistula of a Saccular Aneurysm: Case Study and Literature Review

Primary aortoenteric fistula is a direct communication between the aorta and intestinal lumen and it represents a rare but potentially lethal complication of an abdominal aortic aneurysm. However, it may occur less frequently in a naive non-aneurysmatic aorta. Diagnosis is often difficult and delayed in most cases, unless there is a high level of clinical awareness. Urgent surgery is still the recommended treatment. We describe the case of primary aortoenteric fistula of a saccular aneurysm. A 55-year-old woman was referred to our center with hematemesis, melena, and severe anemia who was dignosed previously with unknown saccular abdominal aneurysm.

Development of tissue-engineered self-expandable aortic stent grafts (Bio stent grafts) using in-body tissue architecture technology in beagles

In this study, we aimed to describe the development of tissue-engineered self-expandable aortic stent grafts (Bio stent graft) using in-body tissue architecture technology in beagles and to determine its mechanical and histological properties. The preparation mold was assembled by insertion of an acryl rod (outer diameter, 8.6 mm; length, 40 mm) into a self-expanding nitinol stent (internal diameter, 9.0 mm; length, 35 mm). The molds (n = 6) were embedded into the subcutaneous pouches of three beagles for 4 weeks. After harvesting and removing each rod, the excessive fragile tissue connected around the molds was trimmed, and thus tubular autologous connective tissues with the stent were obtained for use as Bio stent grafts (outer diameter, approximately 9.3 mm in all molds). The stent strut was completely surrounded by the dense collagenous membrane (thickness, ∼150 µm). The Bio stent graft luminal surface was extremely flat and smooth. The graft wall of the Bio stent graft possessed an elastic modulus that was almost two times higher than that of the native beagle abdominal aorta. This Bio stent graft is expected to exhibit excellent biocompatibility after being implanted in the aorta, which may reduce the risk of type 1 endoleaks or migration.

Antibiotics and Drainage for Treating Stent-Graft Infection after EVAR

The patient was a 64-year-old man. He developed fever and lumbago 6 months after the EVAR. Because CT showed an abscess in the aortic aneurysm surrounding the stent graft, stent-graft infection was diagnosed, and treatment with intravenous antibiotics was initiated. However, the fever and inflammatory markers persisted; therefore, CT-guided drainage catheter placement was performed. After all the pus had been discharged, the fever subsided, and the inflammatory reaction was also suppressed. One year has elapsed since the treatment, and the patient continues to visit with no complaints. We report that stent-graft infection was relieved with antibiotics and drainage.

Aorto-enteric fistulas: a physiopathological approach and computed tomography diagnosis

Infection of an abdominal aortic prosthesis with an enteroprosthetic fistula is a very serious, life-threatening complication, leading sometimes to severe functional consequences, the most serious being amputation. Since the symptoms, if there are any, are often rather non-specific, diagnosis is frequently difficult and has always to be based on a whole series of justifications. Early diagnosis is essential and this fistula should be the first possibility considered in a patient with an abdominal aortic prosthesis who is presenting rectorrhagia or melaena (even if only to a slight degree), sepsis and/or abdominal pain. Although rare, the clinical existence of hypertrophic osteoarthropathy may assist diagnosis. A CT scan is the examination of choice, the criteria providing evidence of a fistula being the presence of gaseous images in a periprosthetic fluid collection, thickening and/or retraction of the intestinal walls in contact, the existence of a false aneurysm, and finally, very rarely, extravasation of contrast agent into the intestinal lumen. The differential diagnoses that may mimic a fistula need to be well known, and can include retroperitoneal fibrosis, an infectious aneurysm, inflammatory or infectious aortitis, and above all, a 'simple' prosthesis infection without fistulisation.

Diverse presentation of secondary aortoenteric fistulae

Secondary aortoenteric fistula, due to mechanical erosion or infection of a prosthetic graft, is a very rare cause of gastrointestinal bleeding and an uncommon complication of abdominal aortic aneurysm repair. A retrospective chart review conducted at our institution revealed 5 cases of secondary AEF occurring between 2006 and 2010. Presentations were diverse, including hematemesis, coffee-ground emesis, and unexplained sepsis. Delay in diagnosis was common. In reporting these cases, we seek to highlight the diverse clinical spectrum and potentially misleading features of this condition. Clinicians must retain a high index of suspicion to avoid potentially catastrophic outcomes.

Aortoesophageal fistula after endovascular aortic aneurysm repair of a mycotic thoracic aneurysm

Mycotic aneurysms constitute a small proportion of aortic aneurysms. Endovascular repair of mycotic aneurysms has been applied with good short-term and midterm results. However, the uncommon aortoenteric fistula formation remains a potentially fatal complication when repairing such infective aneurysms. We present the case of an 80-year-old woman with thoracic and abdominal aortic mycotic aneurysms, which were successfully treated with endografting. However, the patient presented 3 months later with upper gastrointestinal bleeding secondary to erosion of the thoracic graft into the oesophagus. The patient was treated conservatively due to the high risk of surgical repair. There is currently little exposure to the management of mycotic aortic aneurysms. If suspected, imaging of the entire vasculature will aid initial diagnosis and highlight the extent of the disease process, allowing for efficient management. Aortic endografting for mycotic thoracic aneurysms is a high-risk procedure yet is still an appropriate intervention. Aortoenteric fistulae pose a rare but severe complication of aortic endografting in this setting.